This has been already discussed several times on the KLAX forum:
If you already made any customization at KLAX before we added SODE jetways to KLAX, your own customization (which we don't remove automatically), is taking precedence over the one we made that adds SODE jetways, so you must remove your customization, which is a file named KLAX-xxxx*.ini in the %APPDATA%\Virtuali\GSX folder, in order to allow the customization that comes with the scenery to work.